1. Field of the Invention
The present invention provides novel 4- and 5-substituted 1,2,3-triazole moieties, with at least one remote polymerizable moiety. The novel compounds are prepared by the ligation of azides and alkynes using 1,3-dipolar cycloaddition reactions. Alkyne moieties with a terminal reactive functionality are reacted with organic moieties with a terminal leaving group and an azide to provide a mixture of 4- and 5-substituted regioisomers of 1,2,3-triazole moieties. A remote polymerizable moiety may be present in the alkyne moiety, the organic moiety, or the azide, or mixtures thereof, to provide a mixture of 4- and 5-substituted regioisomers of 1,2,3-triazole moieties, with at least one remote polymerizable moiety. The mixture may also then be reacted with a precursor to a polymerizable moiety to provide a wide variety of useful mixtures of 4- and 5-substituted regioisomers of 1,2,3-triazole moieties, with at least one remote polymerizable moiety. The novel mixtures of 4- and 5-substituted regioisomers can be separated by chromatography to provide the purified 4- and 5-substituted 1,2,3-triazole moieties. The novel mixtures of 4- and 5-substituted regioisomers of 1,2,3-triazole moieties, and the purified 4- and 5-substituted 1,2,3-triazole moieties, with at least one remote polymerizable moiety, can be converted to a wide variety of useful polymers. The novel compounds of the invention can be employed in a wide variety of compositions.
2. Description of Related Art
The ligation of azides and alkynes using a 1,3-dipolar cycloaddition reaction (azide/alkyne chemistry) has been described in United States patent application 2005/0222427 and in EP patent 1507769. The reaction involves ligation of azides and alkynes in solution using a copper (I) salt catalyst [Cu(I)], or a copper (II) salt catalyst [Cu(II)] in the presence of a reducing agent, such as sodium ascorbate, to provide triazole polymer moieties under ambient conditions (“click reaction”), see H. C. Kolb, M. G. Finn and K. B. Sharpless, Angew. Chem. Int. Ed. 2001, 40, 2004-2021. The advantage of the copper catalyzed method over the uncatalyzed method is said to be rate acceleration and exclusive 1,4-regioselectivity. These references also describe azide/alkyne ligation chemistry for the preparation of triazole polymer moieties as metal adhesives using Cu(I) catalysts, prepared by reducing Cu(II) or by oxidizing copper metal to Cu(I) in situ, see D. D. Diaz, S. Punna, P. Holzer, A. K. McPherson, K. B. Sharpless, V. V. Fokin, M. G. Finn, J. Polym. Sci: Part A: Polym. Chem. 2004, 42, 4392-4403. References that describe the preparation of vinyl-1,2,3-triazole moieties include G. Wouters, et al., Makromol. Chem. 183 1861-1868 (1982); Raymond J. Thibault, et al., J. Am. Chem. Soc. 2006, 128, 12084-120585; and Kenichi Takizawa, et al., J. of Polym. Sci.: Part A: Polym. Chem., Vol. 46, 2897-2912 (2008).
The copper catalyzed azide/alkyne chemistry requires relatively mild reaction conditions that are not sensitive to air or moisture in contrast to the conditions used in radical polymerizations that are often inhibited by oxygen, leading to incomplete polymerization and reduced yield. Nevertheless, the copper catalyzed azide/alkyne chemistry reactions require the disposal of the catalyst and/or solvent, which adds steps to the synthetic method. It would advantageous to have a method that did not require removal of a catalyst or organic solvent. It would be advantageous also to have a method to prepare 1,2,3-triazole moieties with new polymerizable moieties. Such a method would be useful whether the 1,2,3-triazole moieties are prepared with or without a catalyst.